Environmental sound
testing and training with patients with cochlear
implants

The purpose of this study is
to 1) investigate if computerized training with environmental sounds vs.
speech leads to an improvement in the perception of these sound classes in
cochlear implant patients, 2) investigate if the improvement is
symmetrical (does speech training also affect environmental sounds and
vice versa), and 3) investigate the relationships among speech,
environmental sound perception, temporal and spectral psychoacoustic and
cognitive measures.

Temporal fine structure and music in patients with
cochlear implants

The purpose of
this study is to 1) investigate the reliability of Appreciation of Music
in Cochlear Implantees (AMICI) using test-retest and parallel forms
methods, and 2) investigate cochlear implant implantees' ability to
discriminate changes in stochastic patterns of temporal fine-structure
modulation, and 3) to study the correlation between the two (TFS and music
perception).

A study of the correlation between speech processing
in noise and the ability to discriminate changes in stochastic patterns of
temporal fine-structure modulation in normal, hearing-impaired, and
elderly listeners.

Fz vs.
Cz montage differences with Biomark

The purpose of this study is to see if
normative data obtained with the Cz montage in Biomark is equivalent
to the data obtained with the Fz montage. The reason for this
study is because the Fz montage seems more practical
clinically.

Impedance differences with Biomark

The purpose of this study is to see if Biomark normative
data obtained with low impedance values is equivalent to data obtained
with higher impedances. The reason this study is important clinically is because testing
children is, at times, somewhat of a challenge. Young children, especially those with
multiple impairments, have difficulty sitting still for long
periods of time. The benefits of using higher impedance values
include a more time-efficient testing as well as a more
efficient method for testing children.

Biomark and background
noise

The
purpose of this study is to evaluate
the effect of background noise on the speech-evoked auditory brainstem response using the Biological
Marker of Auditory Processing (BioMARK) software. The BioMARK software is a tool that objectively
assesses the neural processing of sound at the level of the
brainstem (BioMARK Manual). The BioMARK evaluates timing, pitch, and timbre of the
transient and frequency following response evoked by the speech stimulus.
Research has shown that children with reading impairments or auditory processing disorders have
a different response pattern compared to normal developing peers.
Specifically, these children demonstrate delays in timing and timbre encoding impairments. Based on
these findings, the utilization of the BioMARK software will most likely occur in
settings such as schools and clinics. While a quiet setting is ideal, the
possibility of these environments to be noisy is likely. Because of this,
it is important to evaluate the effect of varying levels of background
noise on the BioMARK speech-evoked auditory brainstem
response.

Perception of
environmental sounds and speech in patients with cochlear implants

Limited research has investigated cochlear implant (CI) patients' ability to perceive environmental sounds. In this study, environmental sound perception is assessed with a large-item test composed of 40 sound sources, each represented by four different tokens. The relationship between speech and environmental sound perception and the role of working memory and basic auditory abilities was examined based on patient performance on a battery of speech tests (HINT, CNC, and individual consonant and vowel tests), tests of basic auditory abilities (audiometric thresholds, gap detection, temporal pattern and temporal order tests), and a backward digit recall test. The results will demonstrate CI patients' ability to perceive environmental sounds, indicate the strength of association between speech and environmental sound perception, and the extent to which basic auditory abilities may be involved in mediating this association.

Effects of training on the
identification of spectrally impoverished environmental sounds

Listeners' ability to identify the sources of environmental sounds suffers considerably when sounds' spectral resolution is decreased. Spectral resolution needed for the identification of a large number of common environmental sounds requires a greater number of frequency channels than can be provided by any available cochlear implant. The lack of sufficient spectral resolution limits cochlear implant listeners' ability to know what is happening in their environment (what objects and events are making sound), and decreases their awareness of the environment. This research project is designed to test the hypothesis that identification of spectrally impoverished environmental sounds can be improved through training. It is further designed to determine whether training effects obtained with specific sounds can generalize to other sounds, and compare performance of cochlear implant users to normal-hearing listeners tested with acoustic simulations.

Perceptual processing of
simultaneously occurring sounds

In most cases, human auditory perception takes place in an environment where multiple independently produced sounds are competing for our attention. Successful performance on a number of real life tasks often requires attending to several simultaneous sound streams in order to find the one containing relevant information. Existing auditory perception tests, however, have only marginally addressed listeners' ability to simultaneously perceive information from multiple sound streams. Thus, the goal of this project is to determine whether listener ability to detect a change in a sound stream changes as a function of the number of sound streams present, and existing expectations of which stream will contain a change.